code: def test_join(how, shuffle_method):
      # Make simple left & right dfs
      pdf1 = pd.DataFrame({"x": range(20), "y": range(20)})
      df1 = dd.from_pandas(pdf1, 4)
      pdf2 = pd.DataFrame(
          {"z": range(10)}, index=pd.Index(range(10), name="a")
      )
      df2 = dd.from_pandas(pdf2, 2)
  
      # Partition-wise merge with map_partitions
      df3 = df1.join(
          df2.clear_divisions(),
          on="x",
          how=how,
          shuffle_method=shuffle_method,
      )
  
      # Check result with/without fusion
      expect = pdf1.join(pdf2, on="x", how=how)
      assert_eq(df3, expect, check_index=False, check_dtype=False)
  
imports: from __future__ import annotations
  import numpy
  import pandas
  import pytest
  import dask.dataframe
  from dask.dataframe._compat import PANDAS_GE_210
  from dask.dataframe.utils import assert_eq
label_desc: Use image node_id 19 for calling a global function with example usage: test_join(how, shuffle_method) without return types